Receive the latest entertainment-news updates in your inbox

Filming the harrowing wilderness epic "The Revenant" was like "rock climbing without a rope," director Alejandro González Iñárritu told a robust crowd on Monday at one of the first public screenings of the film.

"There is no way down," Iñárritu said. "You have to go up or you die. There was no choice for us."

After the credits rolled and the audience stood up to cheer, Iñárritu was joined on the Samuel Goldwyn Theatre stage at the Academy of Motion Picture Arts and Sciences by stars Leonardo DiCaprio, Will Poulter and other members of his filmmaking team, who braved a brutal British Columbia winter to shoot the film this past year. He put the final touches on the film last week for its Oscars-qualifying limited release on Dec. 25 followed by a nationwide expansion in January.

Set in 1823, "The Revenant," based on a 2002 novel by Michael Punke, follows Hugh Glass (DiCaprio) and a team of fur trappers (including Poulter, Tom Hardy, and Domhnall Gleeson) on an expedition cut short by a vicious ambush — the first scene that they shot. Soon after, Hugh is mauled by a bear and left for dead by his fellow frontiersman. He wills himself to survive and endeavors to enact revenge on those who have wronged him.

"This is a very linear, straightforward, brilliantly simplistic screenplay...we wanted to find the poetry in between that," DiCaprio said of his performance, which requires very little dialogue for a 151 minute movie. "It was about us immersing ourselves in nature and putting ourselves as close as we could to the struggle of these people and finding the thru line in that process."

That immersion wasn't exactly a pleasant experience all of the time. Not only were the conditions trying and "absolutely against (the crew) all the time," but Iñárritu was uncompromising in his stylistic ambitions — he and cinematographer Emmanuel Lubezki shot everything in natural light and with the painstaking detail of his signature long takes.

It proved to be a very different experience than that of "Birdman," which earned Oscars for Iñárritu and Lubezki.

"In 'Birdman' we were in the cozy corridor of the set. Everything was controlled," said Iñárritu. "The odyssey of making this film became even bigger than what these guys were going through."

For the actors, too, shooting "The Revenant" was a feat unlike that of any other film, with elaborate rehearsals and preparation months out only to have minutes to shoot on the day.

"It's all a beautiful blur to me," DiCaprio said, likening executing Iñárritu's long shots to performing theater every day. "You have to rehearse meticulously and then it's a mad, intense scramble to capture this magic light, this precious hour and a half...It became very much like an un-humorous 'Saturday Night Live' situation."

Holiday 2015: Tech & Gadget Gifts Under $100

The tension of getting the shot right translates into the movie and the performances, DiCaprio said and was a bonding element between the cast and crew.

"This is the most difficult film, I think, that any of us have ever done."